A large French nutrition study has tied higher intake of several common food preservatives to increased rates of high blood pressure, adding a cardiovascular question mark to ingredients that show up all over processed food labels.
The work, led by researchers at Sorbonne Paris Nord University and Université Paris Cité, analyzed data from the NutriNet-Santé cohort, which followed 112,395 participants for a median of 7.9 years. The researchers looked at preservative consumption and later diagnoses of hypertension and cardiovascular disease, including heart attack, stroke and angina.
Food preservatives are not niche chemistry. Open Food Facts, an open food database, says more than 20 percent of processed foods and beverages in its database include at least one preservative. The labels usually look boring: potassium sorbate, citric acid, L-ascorbic acid, sodium nitrite. Boring is not the same as biologically inert.
What the study found
The research team grouped preservatives into two broad buckets. Non-antioxidant preservatives, including sorbates, nitrites and sulfites, are used to slow mold and bacterial growth. Antioxidant preservatives, including ascorbic acid, citric acid and erythorbates, are used to limit oxidation and discoloration.
According to the researchers, 99.5 percent of participants consumed at least one preservative during the first two years of the study. During follow-up, they recorded 5,544 cases of hypertension and 2,450 cases of cardiovascular disease. The cardiovascular cases included 1,142 cerebrovascular events and 1,308 cases of coronary artery disease.
Participants with the highest intake of non-antioxidant preservatives had a 29 percent higher risk of hypertension than those with the lowest intake, the analysis found. They also had a 16 percent higher risk of overall cardiovascular disease. For antioxidant preservatives, the highest-intake group had a 22 percent higher risk of hypertension.
The team also examined 17 commonly consumed preservatives one by one. Eight were associated with higher hypertension risk:
- Potassium sorbate, E202
- Potassium metabisulfite, E224
- Sodium nitrite, E250
- Ascorbic acid, E300
- Sodium ascorbate, E301
- Sodium erythorbate, E316
- Citric acid, E330
- Rosemary extract, E392
Among those, ascorbic acid was also linked to increased cardiovascular disease risk. The study also estimated that about 16 percent of the association between non-antioxidant preservatives and cardiovascular disease was indirectly mediated through hypertension, meaning the researchers’ model points to blood pressure as one possible pathway.
The caveat file is not optional
The study is observational. It can identify associations, not prove that preservatives caused hypertension or cardiovascular disease. That distinction does real work here, because people who eat more processed foods may differ from other participants in ways that are hard to fully strip out with statistics.
The cohort also was not a clean mirror of the general population. Women made up 78.7 percent of participants, and the study included a relatively high share of highly educated people. The researchers said their models adjusted for many potential confounders and that the findings held across multiple sensitivity analyses.
Anaïs Hasenböhler, the doctoral researcher who led the study, said in a European Society of Cardiology press release that experimental work has suggested some preservative additives may harm cardiovascular health, but human evidence has been limited. She said the team believes this is the first study to examine links between a broad set of preservatives and cardiovascular health.
Mathilde Touvier, research director at the French National Institute of Health and Medical Research, said in the same release that the results support a review of the risks and benefits of these additives by regulators including the European Food Safety Authority and the US Food and Drug Administration. She also said the findings support existing recommendations to prefer nonprocessed or minimally processed foods and avoid unnecessary additives.
That is a cautious ask, and it should be. The study does not turn citric acid into a villain. It does put regulators on notice that “permitted additive” should not be treated as the end of the inquiry when exposure comes from many products, repeatedly, over years.
This story draws on original reporting from WIRED.
